In general, an air conditioner is an electronic appliance for maintaining indoor air at pleasant temperature using a cooling cycle of refrigerants. The air conditioner includes an indoor unit, an outdoor unit, and a refrigerant pipe, wherein the indoor unit includes a heat exchanger, a blower fan, etc. and is installed indoor, the outdoor unit includes a heat exchanger, a blower fan, a compressor, a condenser, etc. and is installed outdoor, and the refrigerant pipe connects the indoor unit to the outdoor unit and circulates refrigerants.
The air conditioner can be classified into a stand type air conditioner in which an indoor unit is installed on the floor, a wall-mounted air conditioner in which an indoor unit is mounted on a wall, and a ceiling type air conditioner in which an indoor unit is mounted on a ceiling, according to places where the indoor unit is installed. In the ceiling type air conditioner, the indoor unit is embedded into or hung on the ceiling.
Since the indoor unit of the ceiling type air conditioner is mounted on the ceiling, an inlet for inhaling indoor air, and an outlet for discharging air heat-exchanged through the heat exchanger to the indoor space are disposed in the lower part of the main body. The indoor unit of the ceiling type air conditioner can be classified into a 1-way type with a single outlet and a 4-way type with four outlets forming a quadrangle, according to the number of outlets.
Generally, the indoor unit of the air conditioner includes a blade for adjusting a direction in which heat-exchanged air is discharged, in the outlet. The blade is rotatably coupled with one part of the outlet. The blade is coupled with a motor at one end, and receives a rotatory force generated by the motor to rotate.
The blade is configured to be rotatable in both directions. The blade rotates in both directions in the outlet to adjust the movement direction of heat-exchanged air in the up-down direction. However, since the blade is directly connected to the motor, vibrations and noise may be generated when the motor transfers a rotatory force to the blade. Also, when the indoor unit of the ceiling type air conditioner is installed non-horizontally to the ceiling, a connection axis along which the blade is coupled with the motor is misaligned so that vibration sound of the motor and friction sound of the blade may be loudly generated.